1. Field of the Invention
The present invention relates to a solid pickup apparatus with an improved arrangement of light receiving and transfer means.
2. Prior Art
Conventional known solid pickup apparatus includes those of frame transfer and interline types.
As shown in FIG. 1, the former is composed of a photosensitive portion 1 and a charge storage portion 2 provided separately from the photosensitive portion 1. In the photosensitive portion 1, there are horizontally arranged a plurality of photosensitive blocks a.sub.1 -a.sub.n formed with self-scanning type pickup elements performing photosensitive storage and transfer operation, each of the photosensitive blocks a.sub.1 -a.sub.n being covered with a striped color filter. On the other hand, the charge storage portion 2 comprises CCD shift registers b.sub.1 -b.sub.n formed adjacently to the photosensitive blocks a.sub.1 -a.sub.n and covered with an aluminum film or the like for shading. Moreover, a read shift register 3 formed of a horizontal CCD shift register is connected to the one end of each of the CCD shift registers b.sub.1 -b.sub.n.
The signal charge generated in the photosensitive portion 1 is controlled by a predetermined transfer drive signal and transferred to the charge storage portion 2. The signal charges equivalent to one image derived from the photosensitive portion 1 are temporarily stored in the charge storage portion 2 and the signal charges equivalent to one line are sequentially outputted through the read shift register 3 to an output terminal 4.
In the case of the solid interline type pickup apparatus shown in FIG. 2, there are provided a plurality of light receiving elements 5 separated from each other, each light receiving element 5 being composed of a photodiode and so on whose surface is covered with a given color filter. The signal charge generated in each light receiving element 5 is transferred to a transfer shift register 7 through a transfer gate 6 and then the signal charges equivalent to one line are sequentially transferred to a read shift register 8 by the transfer shift register 7. The signal charges thus transferred are sequentially outputted through a read shift register 8 comprising a horizontal CCD shift register, whereby the signal charges equivalent to one image are outputted to an output terminal 9.
In that case, the surface of each transfer shift register 7 is shaded by an aluminum film to prevent any noise component derived from external light from mixing with the signal charge.
In the frame transfer type solid pickup apparatus, the photosensitive portion 1 functions as an accumulator for accumulating the signals resulting from photoelectric conversion and a transferer for transferring the mass of the signal charge thus accumulated to the charge storage portion 2. In consequence, the effective accumulating time required for the accumulation of the signal charge cannot be increased and therefore it is difficult to improve the sensitivity. Moreover, since the photosensitive portion is covered with polysilicon for use as a transfer electrode, short wavelength light is particularly prevented from passing therethrough and thereby the sensitivity is restricted.
In the case of the interline type, on the other hand, the presence of the shaded transfer shift register in the light receiving means also makes it difficult to improve light storage efficiency and further the shaded portion causes horizontal resolution to reduce.